A generic instrument of this type is known from EP 1 990 021 A1, wherein in this case, a separate transmitter unit is provided which can be inserted into a sealable interior receptacle of an instrument. Such a solution requires special instruments to be provided and is therefore relatively costly.
Medical instruments such as are provided within the framework of the present invention can—in addition to their actual purpose as instruments—also be used to control treatment-assisting software. In computer-assisted surgery, the person performing the treatment is provided with different image outputs, in most cases by a navigation and/or tracking system in the operating theatre. These image outputs show patient data sets or at least parts of patient data sets, i.e. for example three-dimensional or sectional representations of parts of the patient's body. The patient data sets can be generated either by imaging methods such as for example CT or MR tomography, x-ray, ultrasound or fluoroscopy, or by imageless methods such as tapping a bone surface by means of a registered pointer tool, or using laser scanning. Within the framework of image assistance, it is also for example possible to show instruments or treatment devices in their positional relationship relative to the patient data, so as to visually assist the person performing the treatment. Depending on the progress of the treatment, it is often necessary to display a specific part of the software assistance on the screen output, namely the part comprising the functions which are currently required for the current step in the treatment. The software could also be said to consist of different “pages” which interchange in the course of the treatment. It is often necessary to select particular software pages during the treatment. In addition to the solution mentioned above, this is often also realized by means of an input apparatus such as a mouse or a keyboard or by means of a touch-sensitive screen. Foot switches, virtual keyboards or voice control systems are also known. Other “means of communication” are for example specific movements of tracked instruments, for example pivoting about a fixed point.